The fission yeast Schizosaccharomyces pombe senses glucose availibility through an evolutionarily conserved cAMP-dependent signaling pathway. The long term objective of this work is to define the roles of the S. pombe heterotrimeric G alpha subunit, Gpa2, in glucose-mediated adenylyl cyclase regulation. The hypothesis is that Gpa2 physically interacts with the glucose receptor Git3 through a G beta/gamma dependent mechanism and regulates the activation of adenylyl cyclase to control transcription of the glucose-repressed enzyme, fructose-1,6-bisphosphatase. Using genetic screens, the yeast two-hybrid assay, and co-immunoprecipitation assays that detect protein-protein interactions, a detailed study of the molecular interactions necessary for G protein-mediated signal transduction will be carried out. The powerful genetic techniques available to the study of S. pombe make it an ideal system for dissecting the intricate nature of molecular communication networks at the cellular level. Defining the molecular mechanisms utilized in S. pombe to control gene expression promises to not only advance and challenge our current knowledge of how cells respond to changing environments but, could potentially uncover medically important therapeutic targets. [unreadable] [unreadable]